Muon g − 2 , rare kaon decays, and parity violation from dark bosons

• Published in: Physical review. D, Particles, fields, gravitation, and cosmology Particles, fields, gravitation, and cosmology, 2014-05, Vol.89 (9), Article 095006
• Main Authors: Davoudiasl, Hooman, Lee, Hye-Sung, Marciano, William J.
• Format: Article
• Language: English
• Subjects: Bosons; Channels; Decay; Gravitation; Kaons; Muons; Parity; Photons
• ISSN: 1550-7998; 1550-2368
• DOI: 10.1103/PhysRevD.89.095006

The muon g sub( mu ) - 2 discrepancy between theory and experiment may be explained by a light vector boson Z sub(d) that couples to the electromagnetic current via kinetic mixing with the photon. We illustrate how the existing electron g sub(e) - 2, pion Dalitz decay, and other direct production data disfavor that explanation if the Z sub(d) mainly decays into e super(+)e super(-), mu super(+) mu super(-). Implications of a dominant invisible Z sub(d) decay channel, such as light dark matter, along with the resulting strong bounds from the rare K arrow right [pi] + missing energy decay are examined. The K decay constraints may be relaxed if destructive interference effects due to Z - Z sub(d) mass mixing are included. In that scenario, we show that accommodating the g sub( mu ) - 2 data through relaxation of K decay constraints leads to interesting signals for dark parity violation. As an illustration, we examine the alteration of the weak mixing angle running at low Q super(2), which can be potentially observable in polarized electron scattering or atomic physics experiments.